House electric



C. H. CARPENTER.

THREE-PHASE CRUCJBLE FURNACE.

APPLICATION FlLED MAY 22. 1920.

1,4; l 5, 989, Patented May 16, 1922 WTNESSES: INVENTOR j@ Wu& A i g %Cacoenkn AT'TORNEY shell have improved means for conducting ATENT O cmmsron H. CARPENTER, ormwm, PENNSYLVANA, Ass eNoB, TOWESTNG- HOUSE ELECTRIC &VMANIFACTURING COMPANY, a conronmrov or PENN- a sYLvANIA.

1,415,9s9. p Application filed May 22,

i' 'TO (ZZ 'whom 'Et may cmwern:

Be it known that I, CRANSTON H. CARPEN- (rim, a citizen of the United States,' and a resident of Irwin, in the County of' Westmhreland and State of Pennsylvania, have invented a new and useful Improvement in Three-Phase Crucible F urnaces, of which thefollowing is a specification;

My invention relates to electric furnaces and particularly to electric-resistance melting furnaces and it hasfor one of its objects to provide a furnace which shall have an improved resisto' comprising a refractory material to be placed in close ,operative engage-` ment with the material container and which current to and from the resistor and be so designed' that it may be used on either single 4 or' polyphase alternating-current supply circuits, with relatively small* changes in its cbnstruetion i :The ;Wallis of the' ene::

` crucible and a plurality'of wells or hoppers m ke * ;More specifically; my' invention embodies a tiltable container in which a suitable meli; ing crucihle is located. A plurality of refractory resistance' elements s'urround. the" filled with a 'mass of granular electrical 'con ducting material operatively enga 'ngthe resistere, are syminetrically dispose around the resistor. At or near the bottom of each ofithejwells is &suitable terminal electrode made of'carbonaceous material to which the electric supply cenductors may be connected. A suitable cover member for the fumace may also be provided.

Referrlng to the single sheet of drawings, Figure 1 is a cross-sectionalview of the clevice emhoclying my invention on the line" I-I of Fig. 2, and Fig; 2 is-a vertical crosssectional view of tha-same devi'ce taken on The supporting ta; fam comprises an exteriorfmetelfcasmg 1 whch enclosesan outerlshell 2 of heat-insulatingd'ical chamber l ore the me l' ting crucible is commonly lindri-cal .j'infcontoun it is usual to toffthe 'same' general contour and I; have, therefgre howp thel ross-section of the fu Specificaton of Letters Patent.

e material to be melte restof the structure. of'thefurnace I THREEPHASE CRUCIBLE FURNACE.:

Patented May 16, 1922.`

1920. Serial No. 383378.

nace as circulzr in shape,- although this is not necessary A plurality of wells or hoppers 16 are provided in the outer shell 2 'and the inner shell 3, and are so disposed as to be in contact with the cylindrical chamber 4. The number of wells or hoppers' is'selected in accordance with the number of supply-circuit conducto's which; of course, depends upon the nuning' refractory 'resistance members 8 which may be made'of carborundum or of silicon carbid. "As shown in Fig. 1, .each of theresistor members &covers` substantially onethird of the periphery of thejjcrucible 5 and the periphery of the cruis, therefore,.adapted tdoperte `on a'three phase 'sipply'circui p :4

'Ator near the bottom of each of the hoppers 6 is placed &solid carbn a'ceous termi'- -nalgeltrode' 9 towhicha corresponcling -supply circ'uit, conductor' 10 'may be suitabl connected; .A mass ofgranularelectrica conducting materialll, such as graphite or coke, is placed in each of'the hoppers 6 and may be suitably tan ped therein to conduct the current `from the terminal electrode 9 to and from the endsflof the -resistor members 8. As a small space is provided between the adjacent ends of each of the resisto'r mem'- i bers 8, they may expend, during operation, t

As shown in 4 without danger of fracture.

Fig. 2, I provide a plurality of resistorfi members 8 located one above another and I desire it to be understoodthat any suitable or desirablenurnber of 'such resitor may be en'ployed :in peralle :9 he object being;

as uniformly as' possible, thus preventing overheating of anv part thereof. i 57 suitable supporting pedestals 12 are proioo vide& which co-operate' withfshort' suspen iy s on members 13 suitablyattached "tot he'j-- metal casing 1 to permfit of. the furnacebe 7 h 'out the niet through a pouring spout videcl in the body member 14, having ing tilted and of pourin' n ot shown) pro I of the furnac. {j 'A over f a' charging dob 15; is-j provided at the top 'of the'furnace' t` `c preventj win cult to provide suitable means for conduct.

ingthe current to and from such resistere, and, as lt s highly desrable to use terminel electrodes towlnch the supplyrrcuit conductors may be connected, it becomes necessary to provide` current-conducting means therehetween which Will permit substantially continuous operation of the furnace at relatively high temperature& the terminal electrode is directly connected to the resistor, oxidaton of either or both will take place during the operation of the furnece, resulting in e poor contact therebetween and necessitating frequentattention thereto. granuler material, such as graphite 017 coke, 'which may .be thoroughly tamped in place,

rovides ajlzrge number of current-conducting paths through the resistor and, ,if any oxidation of either the rcsistor or the gra nu- .lar material takes place, -it may 'be' retamped and may beeesily and quickly removed and replaced whenever this becomes necessary efter e reletvely long period of operation of the furnace. a x .30 It Will be noted that I provide a new and' improved form of refractory resistor which may be located in close operative contact With the material container and that I provide new means for conclucting the current from the terminal eleetrode to the resistor proper. l

'various modifications may be made in the `device exnbodying my invention without de parting from the sprt and scope thereo 40 end. I desre that only such, lntations'shall he placed thereon as are imposed by the pror'art or are specifically set fortli, in the eppcnded cmime.

I I claim :tsjny invention: I

1. In en electric furnacc, thecombinzton With a contciner, of a resistor surrounding seid contaiu., a plurality of Welle sym- :metricaily dieposed around said containe', grenulur electrical-conducting material contained in seid Welle and. operatively en ;3: ing said 'esistor, and terminal electrodes in `^l Welle aCapted to connect said resstor to a source of electromotive force.

lu {AB ch *ric furnace, the combination with a conte 3 of a resister adjacent said contener comprising solid retractory electricel-cond g material, a plurality of :elly disposed around said urodes in said Wells adapted lo he connected` to e source of electromotive force, end a mass of granular electricalj-ox llueting material intcrposed between each of the electrodes and the resistor.

ti, In an electric furnace, the conbination materal, a plurality of hoppers adjacent to,

The use of finely divided with e container, of e resistor acljacent said T. 131598&

'granular' electrical-conducting material interposed between each. of the electrodes and the resisto'.

4. -In an electric fu'nace, the combination With a container and means for tilting the container, of a resstor adjacent to, and surrounding, said container and' comprising blocks of refractory electrical-conducting and symmetrically disposed around, said container, lectrodes in'said hoppers adapted to, be'onnected to e sourceof electromotve force, and a mass of granular electrcal-conductng material interposed between each of the, electrodes\ and the resistor.

5. In an electr'c furnace, the combination With e container having an open end and means :for tiltng the container, of a, re ristor adjacent to, and surrounding, said container and compris'ing solid refraetory electrical-conducting material, a pluralty of hoppers adjacent to, and symmetrically disposed around, said. container,` electrodes in said hoppers ad'apted to be connected to a source of. electronotive force, a mass of granular electrical--conductng material interposed between each of the electrodes and the resistor, and leatnsulating means entirely surrounding said .container.

6. In an electric furnace, the combinztion With refractory heat-nsulating casing, a crucible in said casing, and mea-nsfor tilting said casing, of a resistor in said casing adjacent said crucible, a plurality of hoppers adjacent to, and symmetrioally disposed around, seid crucible, electrodes in said hoppero, e mass of grunular electr ical-conducting material in; said hoppers interposecl between said electrodes andeaid resistor, and cover-ing means for said casng and said crucible.

7. In an eleotric furnace, the comhination With e crucible, of -a resistor disposed. adjacent to said crucible and comprising solid refractory electrcal-conducting material, a plurality of Wells symnietrically disposed around said crucible, solid 'carboneoeous electrodes contained in 'said Welle and adapt ed to be connected to a. Source of polyphase electromotive force, and a mass of granul ar electr'ca'l-conducting material interposed between each' of the elect-rocles and the resistor.

8. In an electric-resistance furnece, the! combination With a. crucible, of a. resistor surrounding said cruoble and comprising ,blocks of solid refractory electrical-'conducting material, three Wells symmetrically disposed around said crucihle, solid carbone'- oeous electrodes contained in seid wells and i adapted to be connected to a source of threephase electromotwe force, and .a mass of granulr electrical-conducting material interposed between each of the electrodes and the resistor.

9. In an elect'ic-"esistance fu'mce, the conbination with a c-ontziner, of a resstor enc'rclingsad container and consstng of a plu'ality of blocks of ref'actory electricalconducting material of arcuate form, the

`angular extent of -ezwh block beingdeten mined in accqrdanee with the number of phases of the supply c'cuit.

CRANSTON H. CARPENTER; I 

